Task optimization in remote health monitoring systems

ABSTRACT

Systems, methods, and devices are disclosed that monitor the health status of patients. Dynamic task management functions apply data analytics to discretize continuous data values from monitored patients, and apply association rule mining techniques to prioritized required user tasks, to minimize the number of daily action items required by patients. The remaining action items maximize information gain, thereby improving the overall level of patient adherence and satisfaction without losing health monitoring effectiveness.

CROSS-REFERENCE(S) TO RELATED APPLICATION(S)

This application is a National Stage Entry of PCT/US2013/056901, filedAug. 27, 2013, which claims the benefit of U.S. Provisional ApplicationNo. 61/694,183, filed Aug. 28, 2012, the entire disclosure of which ishereby incorporated herein by reference for all purposes.

STATEMENT OF GOVERNMENT LICENSE RIGHTS

This invention was made with Government support under Grant NumberLM007356, awarded by the National Institutes of Health. The Governmenthas certain rights in the invention.

BACKGROUND

Chronic diseases such as heart failure, diabetes, cancer, and stroke arethe leading causes of death and disability in the United States. Morethan 70% of deaths among Americans are caused by chronic diseases andmore than 133 million Americans, or about 1 out of 2 adults, have atleast one chronic disease. Costs of chronic illness are also hard toneglect. In the United States, heart failure cost $39.2 billion in 2010,and diabetes cost $174 billion in 2007. Early diagnosis and treatmentcan improve quality of life and life expectancy for people with chronicdiseases. Treatment usually involves lifestyle changes such ascollecting biomedical readings, taking medicines, regulating diets, anddoing regular physical activity.

Remote health monitoring has led to an improved quality of life, ahigher efficiency, and an increased accessibility for healthcareprofessionals to patients with chronic diseases. For patients withchronic diseases, remote health monitoring systems provide remotesensing and data processing to make health status monitoring, dataanalysis, guidance, and emergency prevention available at home, withoutrequiring the presence a full-time professional caregiver. These systemscollect biomedical data that may be delivered to a central server forstorage and analysis. This analysis is used centrally by caregivers toremotely monitor and assess their patients' health. If an abnormality inthe patient's health is detected by the remote health monitoring systemor noticed by a caregiver based on the information collected by theremote health monitoring system, the patient can be prompted to change adose of a medication, to alter a level of physical activity, or to takeother steps for addressing the abnormality. Such patient guidance canlead to significant improvements in patient health.

In the remote health monitoring domain, patients are required to performdaily tasks provided by their health care professionals. For manyreasons, it may be desired to gather a large amount of data from apatient, and to provide many daily tasks to be performed. However, taskcomplexity and difficulty can affect user participation andsatisfaction. If a patient is presented too many tasks, it is morelikely that the patient will skip some of the tasks or stop using theremote monitoring system altogether. Such system non-use can severelydegrade the effectiveness of the designed system, and missing data canlead to biased and dangerous conclusions.

What is needed are techniques for reducing the number or complexity oftasks a patient must perform while nevertheless obtaining adequatemonitored information from the patient to generate meaningfulpredictions about patient health.

SUMMARY

This summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This summary is not intended to identify key features ofthe claimed subject matter, nor is it intended to be used as an aid indetermining the scope of the claimed subject matter.

In some embodiments, a computer-implemented method of optimizing datacollection tasks for patient monitoring is provided. A set of datacollection tasks are performed by a computing device to obtain a set ofmonitoring data. The set of monitoring data is processed by a computingdevice to detect one or more association rules between two or more datacollection tasks in the set of data collection tasks. The set of datacollection tasks is optimized by a computing device based on thedetected association rules. In some embodiments, a computer-readablemedium is provided having computer-executable instructions storedthereon that, in response to execution by one or more processors of acomputing device, cause the computing device to perform such a method.

In some embodiments, a system for patient monitoring is provided. Thesystem for patient monitoring comprises a patient data processing systemand a task optimization system. The patient data processing system andthe task optimization system each include at least one computing devicethat comprises at least one processor and a memory. The at least onecomputing device of the patient data processing system is configured toretrieve a set of data collection tasks from a task data store; performthe set of data collection tasks to obtain a set of monitoring data; andstore the set of monitoring data in a patient data store. The at leastone computing device of the task optimization system is configured toretrieve the set of monitoring data from the patient data store; processthe set of monitoring data to detect one or more association rulesbetween two or more data collection tasks in the set of data collectiontasks; optimize the set of data collection tasks based on the detectedassociation rules; and store the optimized set of data collection rulesin the task data store.

DESCRIPTION OF THE DRAWINGS

The foregoing aspects and many of the attendant advantages of thisinvention will become more readily appreciated as the same become betterunderstood by reference to the following detailed description, whentaken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a block diagram that illustrates an exemplary embodiment of aremote health monitoring system according to various aspects of thepresent disclosure;

FIGS. 2A-2E are a flowchart that illustrates an exemplary embodiment ofa method of optimizing health monitoring tasks according to variousaspects of the present disclosure;

FIG. 3 is a table that illustrates an acceptable range for blood glucosevalues and four questions that were presented along with their discreteanswer value choices for a test of an embodiment of the presentdisclosure;

FIG. 4 is a table that illustrates discretized timestamp periods alongwith mean and standard deviation values of three different blood glucoselevels for the test of the embodiment of the present disclosure;

FIG. 5 is a chart that illustrates a count of first order logic rulesadded for various time window values for the test of the embodiment ofthe present disclosure;

FIG. 6 is a table that illustrates a set of logic rules determinedduring the test of the embodiment of the present disclosure; and

FIG. 7 is a block diagram that illustrates aspects of an exemplarycomputing device appropriate for use with embodiments of the presentdisclosure.

DETAILED DESCRIPTION

The present disclosure describes task optimization technology thatcombines data discretization methods and first-order logic to reducepatient burden in using remote health monitoring systems. Data miningtechniques are applied to remote health monitoring systems in order tooptimize data gathering tasks performed by patients. Optimized output ofsuch a remote health monitoring system includes a minimal number oftasks which maximize information gain.

System Overview

FIG. 1 is a block diagram that illustrates an exemplary embodiment of aremote health monitoring system 100 according to various aspects of thepresent disclosure. As illustrated, the remote health monitoring system100 includes three tiers: a patient monitoring system 102, a patientdata processing system 104, and a task optimization system 106. Each ofthe systems 102, 104, 106 may include one or more computing devicesconfigured to provide the engines, data stores, and/or servicesillustrated and described herein as part of the respective system 102,104, 106.

The patient data processing system 104 is configured to send one or moredata collection tasks to the patient monitoring system 102, which causethe patient monitoring system 102 to collect particular measurementsform the patient 90, and to transmit the collected information to thepatient data processing system 104 for processing and storage. The taskoptimization system 106 is configured to access the collectedinformation stored by the patient data processing system 104, to processthe collected information to detect one or more association rules, andto use the detected association rules to optimize the data collectiontasks.

In some embodiments, the patient monitoring system 102 may be located atthe patient's home (or otherwise placed in a location easily accessibleto the patient), while the patient data processing system 104 and thetask optimization system 106 are placed in a central location such thatmultiple patient monitoring systems 102 in multiple locations may sharethe resources of a single patient data processing system 104 and/or taskoptimization system 106. In such embodiments, the components of theremote health monitoring system 100 may communicate with each otherusing any suitable communication technology, such as wired or wirelessInternet communication, direct dial telephone or ISDN communication,and/or any other suitable communication technology. In some embodiments,the patient monitoring system 102, the patient data processing system104, and/or the task optimization system 106 may be provided by a singlecomputing device, or by multiple computing devices each located on thesame network, thus obviating the need for long-distance communicationbetween the elements of the system 100. Though FIG. 1 illustratesvarious components as being included in either the patient monitoringsystem 102, the patient data processing system 104, or the taskoptimization system 106, in some embodiments, the illustrated componentsmay be moved from one of the illustrated systems 102, 104, 106 toanother of the illustrated systems 102, 104, 106 or split between two ormore of the illustrated systems 102, 104, 106; two or more of theillustrated systems 102, 104, 106 may be combined into a single system;and/or one of the illustrated systems 102, 104, 106 may be broken intomultiple separate systems.

As illustrated, the patient monitoring system 102 includes one or morephysical data sensor devices 108 and one or more interactive sensordevices 118 for collecting measurements from a patient 90. The physicaldata sensor devices 108 are physical devices that may automaticallyperform a measurement of a physical value, and may cause the detectedphysical value to be automatically transmitted to the patient dataprocessing system 104 without further interaction from the patient 90.For example, the physical data sensor devices 108 may include, but arenot limited to, an electronic sphygmomanometer, an electronicthermometer, an electronic heart rate monitor, a pedometer, anelectronic scale, and/or the like. The interactive sensor devices 110are physical devices that collect information entered by the patient 90(or by a caregiver operating the patient monitoring system 102 on behalfof the patient 90). In some embodiments, an interactive sensor device110 may be configured to present a prompt to the patient 90 to instructthe patient 90 to perform a measurement with a non-connected medicaldevice or answer a survey question, and may subsequently allow thepatient 90 to enter the result of the measurement or the answer thesurvey question. The interactive sensor device 110 then sends thecollected information to the patient data processing system 104. In someembodiments, the interactive sensor devices 110 may include a desktopcomputing device executing a stand-alone application or presenting a website, a mobile computing device such as a smart phone, a tabletcomputing device, a custom computing device configured to present aninterface to the patient monitoring system 102, and/or the like.

As illustrated, the patient data processing system 104 includes a datacollection engine 112. In general, the word “engine” (usedinterchangeably with the word application or module), as used herein,refers to logic embodied in hardware or software instructions, which maybe written in a programming language, such as C, C++, COBOL, JAVA™, PHP,Perl, HTML, CSS, JavaScript, VBScript, ASPX, Microsoft.NET™, and/or thelike. An engine may be compiled into executable programs or written ininterpreted programming languages. Software engines or applications maybe callable from other engines or from themselves. Generally, theengines or applications described herein refer to logical modules thatcan be merged with other engines or applications, or can be divided intosub-engines. The engines or applications may be stored in any type ofcomputer-readable medium or computer storage device and be stored on andexecuted by one or more general purpose computers, thus creating aspecial purpose computer configured to provide the engine orapplication.

In some embodiments, the data collection engine 112 may provide a webservice or other appropriate application programming interface (API)with which the patient monitoring system 102 communicates, such thatdata collection tasks may be transmitted to the patient monitoringsystem 102 and collected data may be received by the data collectionengine 112 via the API. In some embodiments, the data collection engine112 may generate a web-based interface to be presented to the patient 90by the patient monitoring system 102 and into which the collected datamay be directly entered. In some embodiments, the data collection engine112 may cause the raw collected data to be stored, while in someembodiments, the data collection engine 112 may perform filtering orother data cleaning tasks before causing the collected data to bestored. Further functionality of the data collection engine 112 isdescribed below.

The illustrated patient data processing system 104 also includes apatient data store 114, an association rule data store 116, and a taskdata store 118. As understood by one of ordinary skill in the art, a“data store” as described herein may be any suitable device configuredto store data for access by a computing device. One example of a datastore is a highly reliable, high-speed relational database managementsystem (DBMS) executing on one or more computing devices and accessibleover a high-speed packet switched network. However, any other suitablestorage technique and/or device capable of quickly and reliablyproviding the stored data in response to queries may be used, and thecomputing device may be accessible locally instead of over a network, ormay be accessible over some other type of suitable network or providedas a cloud-based service. A data store may also include data stored inan organized manner on a storage medium 708, as described further below.One of ordinary skill in the art will recognize that separate datastores described herein may be combined into a single data store, and/ora single data store described herein may be separated into multiple datastores, without departing from the scope of the present disclosure.

In some embodiments, the patient data store 114 is configured to storethe data collected from the patient 90 by the patient monitoring system102. In some embodiments, the patient data store 114 may also beconfigured to store other information related to patients, such asdemographic information, associated health care provider information,login and password information, and/or the like. In some embodiments,the patient data store 114 may be configured to store data collectedfrom the patient 90 as well as data that has been processed by the taskoptimization system 106.

In some embodiments, the association rule data store 116 is configuredto store association rules detected by the task optimization system 106based on the collected data. In some embodiments, the association ruledata store 116 may also store information about each association ruleindicating the rule's predictive strength, such as a confidence value, asupport value, and/or a conditional probability value. The task datastore 118 is configured to store data collection tasks. Each datacollection task may include a unique identifier, one or moreinstructions for executing the task, and a set of response options. Insome embodiments, the instructions may be directions for a patient 90 toconduct actions, while in some embodiments, the instructions may includecomputer-executable instructions for execution by a physical data sensordevice 108. The unique identifiers of the data collection tasks may beused by the association rules in the association rule data store 116 toreference the data collection tasks. Further aspects of the patient datastore 114, the association rule data store 116, and the task data store118 are discussed below.

As illustrated, the task optimization system 106 includes a datadiscretization engine 120 and an association rule detection engine 122.In some embodiments, the data discretization engine 120 is configured toanalyze collected data that includes continuous data values representingphysiological measurements (i.e., signals that are values on a continuumsuch as a blood pressure value, a heart rate, a blood sugar reading,and/or the like, as opposed to discrete data such as multiple choicesurvey responses) in order to determine how the continuous data valuesmay best be discretized. In some embodiments, the data discretizationengine 120 may also be configured to clean the collected data beforefurther processing. The association rule detection engine 122 isconfigured to analyze the collected data after it has been cleaned anddiscretized in order to detect association rules implied by thecollected data and store the detected rules in the association rule datastore 116. Further aspects of the data discretization engine 120 and theassociation rule detection engine 122 are described below.

Embodiments of the system 100 to optimize tasks are useful for improvingparticipation rates in automated remote monitoring, at least because thesystem 100 may reduce the number of tasks a patient 90 is asked toperform. Also, in some embodiments, the system 100 may be operated by acaregiver, who may be located with the patient, or may instead bemonitoring the patient remotely via telephone, via email, via textmessage, via video conference, or via any other suitable means. Evenwhen operated by a caregiver, the reduction of tasks provided by thesystem 100 can be useful, at least because saving the caregiver time inattending to an individual patient can allow a single caregiver torender care to more patients overall.

Optimizing Tasks Using Association Rules

FIGS. 2A-2E are a flowchart that illustrates an exemplary embodiment ofa method of optimizing health monitoring tasks according to variousaspects of the present disclosure. Broadly speaking, the method 200finds association rules between data collection tasks, and optimizesdata collection tasks for execution to collect information from apatient. In some embodiments, data collection tasks are defined bydomain experts to collect information from patients relevant toparticular health conditions. For example, to remotely monitor thehealth of patients with diabetes, data collection tasks instructing apatient monitoring system 102 to collect blood pressure data, bloodglucose measurement data, body weight data, and data including one ormore survey question responses. As understood by one of ordinary skillin the art, other data may be automatically or interactively collectedby the patient data monitoring system 102 to monitor patients withdiabetes and/or other chronic conditions. Historical data from a set ofpatients is stored by the patient data processing system 104 andanalyzed by the task optimization system 106 to optimize the set of datacollection tasks, thereby increasing the likelihood of patientcompliance while also maximizing information gain from the datacollection tasks performed.

From a start block, the method 200 proceeds to a set of method steps 202defined between a start terminal (“terminal A”) and an exit terminal(“terminal B”), wherein monitoring data is collected from one or morepatients using a set of data collection tasks. From terminal A (FIG.2B), the method 200 proceeds to block 210, where a patient monitoringsystem 102 receives a set of data collection tasks from a patient dataprocessing system 104. In some embodiments, the patient monitoringsystem 102 may request the set of data collection tasks from an APIprovided by a data collection engine 112 of the patient data processingsystem 104, and may be retrieved by the patient data processing system104 from a patient data store 114. In some embodiments, the patient datastore 114 may include sets of data collection tasks that are definedindividually for each patient, while in some embodiments, the patientdata store 114 may include sets of data collection tasks that aredefined to be applicable to groups of patients being monitored forsimilar reasons. The set of data collection tasks may include an orderin which the tasks are to be performed, and may include logic forchoosing a subsequent task based on a value collected for an antecedenttask. In embodiments wherein logic is included in the set of datacollection tasks, the logic may initially not include any logic forskipping tasks until the method 200 has been performed.

Next, at block 212, the patient monitoring system 102 collects dataindicated by the set of data collection tasks using one or more physicaldata sensor devices 108 and/or one or more interactive sensor devices110, according to instructions included in each task of the set of datacollection tasks and any logic provided with the set of data collectiontasks. At block 214, the patient monitoring system 102 transmits thecollected data to a data collection engine 112 of the patient dataprocessing system 104. In some embodiments, the transmission of thecollected data by the patient monitoring system 102 may occurautomatically and without requiring further user interaction. Asdescribed above, the collected data may be transmitted to the patientdata processing system 104 via the internet, a modem, a leased line, orvia any other suitable communication technology. As also describedabove, in some embodiments the data collection engine 112 may provide aweb service or other suitable API to receive the data from the patientmonitoring system 102. At block 216, the data collection engine 112stores the collected data in a patient data store 114. The method 200then proceeds to terminal B.

In some embodiments, the set of method steps 202 described above may beperformed multiple times to gather a set of data to be analyzed for taskoptimization. The repetition of the set of method steps 202 may beperformed with a single patient over a period of time, or may beperformed using data from many patients to provide greater statisticalrigor for the conclusions drawn. In some embodiments, the data to beanalyzed by the remainder of the method 200 may be collected usingtechniques other than those described in the set of method steps 202.

From terminal B (FIG. 2A), the method 200 proceeds to a set of methodsteps 204 defined between a start terminal (“terminal C”) and an exitterminal (“terminal D”), wherein the collected data is cleaned anddiscretized to generate training data. From terminal C (FIG. 2C), themethod 200 proceeds to block 218, where the data collection engine 112cleans the collected data in the patient data store 114. The datacleaning may include detecting data that falls outside of predefinedacceptable ranges (or automatically detected common ranges), detectingdata that indicates system non-use, consolidating or disambiguatingmultiple measurements of the same value, and/or the like. In someembodiments, data cleaning may also include missing data imputation,such as techniques similar to those disclosed in commonly owned,co-pending International Patent Application No. PCT/US2012/052544, filedAug. 27, 2012, which is hereby incorporated by reference herein in itsentirety for all purposes. In some embodiments, the data cleaning may beperformed on stored data, or may be performed while the data is beingcollected or otherwise at some point before the data is stored in thepatient data store 114.

Many types of collected data may be signals that include continuous datavalues associated with timestamps. For example, a blood glucose levelmeasurement may be a value on a continuum indicated by a number ofmilligrams per deciliter (mg/dL). Such a measurement may also beassociated with a timestamp indicating a time of day at which themeasurement was taken. Using the raw values of such data to optimizetasks may be possible, but in some embodiments, it may be desired todiscretize the data to reduce the dimensionality and complexity ofprocessing continuous data values. For example, a continuous bloodglucose level measurement value may be discretized to be either a lowvalue, a normal value, or a high value. Likewise, a timestamp value maybe discretized to be either a morning, afternoon, or evening value.

Accordingly, the method 200 then proceeds to a for loop defined betweena for loop start block 220 and a for loop end block 234. The for loopexecutes once for each signal to be analyzed from the collected datathat includes continuous data values, and assigns a discrete value tothe data according to the continuous data value. In some embodiments, agiven signal may include both a measurement value and a timestamp valueindicating when the measurement was taken. In such embodiments, the forloop discretizes both the measurement value and the timestamp value.

From the for loop start block 220, the method 200 proceeds to block 222,where a data discretization engine 120 of a task optimization system 106determines appropriate timestamp discretization thresholds for thesignal. In some embodiments, appropriate discretization thresholds couldbe predetermined by an expert, and the data discretization engine 120may determine the thresholds by retrieving them from a data storagelocation. In some embodiments, optimal thresholds may be automaticallydetermined using a data mining process. A number of bins and/or a numberof thresholds may be predetermined by a user configuration, may bedetermined by an automatic iterative process, and/or using any othersuitable manual or automatic technique.

One example of a data mining process for automated detection of optimaldiscretization thresholds includes the use of an expectationmaximization (EM) algorithm. The use of the EM algorithm assumes thatthe collected sensor data follows a mixture of Gaussian distributions.The EM algorithm is an iterative method to optimize the estimation of anunknown parameter Θ, given measured variables U and unmeasured variablesJ. The objective of the EM algorithm is the maximization of theposterior probability (Equation 1) of the parameter Θ given U and J.

$\begin{matrix}{\theta^{*} = {{argmax}_{\theta}{\sum\limits_{J}\;{P\left( {\theta,{J\text{|}U}} \right)}}}} & (1)\end{matrix}$

The EM algorithm consists of two steps: The expectation step (E step)and the maximization step (M step). The E step finds a local lower-boundto the posterior distribution while the M step optimizes the boundobtained from the E step using iteration. In the E step, the algorithmcalculates the expected value of the log likelihood function under thecurrent estimate of the parameters Θ^(t) of the conditional distributionJ given U. This step finds the best lower bound, B(Θ|Θ^(t)).

$\begin{matrix}{{{B\left( \theta \middle| \theta^{t} \right)} = {\sum\limits_{J}\;{\frac{{f^{t}(J)}\log\;{P\left( {U,J,\theta^{t}} \right)}}{f^{t}(J)}\mspace{14mu}{while}}}}{{f^{t}(J)} = {\frac{P\left( {U,J,\theta^{t}} \right)}{\sum\limits_{J}\;{P\left( {U,J,\theta^{t}} \right)}} = {{P\left( {{J\text{|}U},\theta^{t}} \right)}.}}}} & (2)\end{matrix}$The M step iterates and chooses Θt⁺¹ by maximizing the bound, B(Θ|Θ^(t))from the E step.θ^(t+1)=argmax_(θ) B(θ|θ^(t))=argmax_(θ)[Q ^(t)(θ)|log P(θ)]  (3)while Q^(t)(Θ) is the expected complete log-likelihood, log P(U,J|Θ) andP(Θ) is the prior on the parameters Θ. Based on mean and standarddeviation values of each Gaussian curve from the EM algorithm, themethod 200 finds intersection points and these points are used forautomated discretization. As noted below in the test results, while someembodiments may use expert determination of discretization thresholds,automatically determined discretization thresholds determined using atechnique such as the EM algorithm may produce more effective results.

Once appropriate timestamp discretization thresholds have beendetermined, the data discretization engine 120 organizes collectedsignal data for the signal into a predetermined number of timestamp binsbased on the timestamp discretization thresholds, such that, forexample, all of the “morning” readings are placed in a “morning bin,”all of the “afternoon” readings are placed in an “afternoon bin,” andall of the “evening” readings are placed in an “evening bin.” Theorganization may be performed using any suitable method, such as addinga discrete value field to each measurement record in the patient datastore 114 so that measurements from each bin may be quickly retrieved inresponse to queries, by copying each measurement in a given bin to aseparate location associated with the given bin, and/or using any othersuitable method. In some embodiments, the measurement data may not befurther copied or updated, but instead the values that denote the cutoffpoints for each bin may be stored so that the measurements from each binmay be retrieved from the patient data store 114 using appropriatelycrafted database queries.

Once the signal measurements have been organized into timestamp bins,the method 200 proceeds to a for loop defined between a for loop startblock 226 and a for loop end block 232. In the for loop, the measurementvalues within each timestamp bin are separately discretized. This may,for example, lead to similar values in different timestamp bins to beassigned different discrete values, depending on the distribution ofcontinuous values within each timestamp bin. For example, a bloodglucose reading of 167 mg/dL may be discretized as a low value in afirst timestamp bin, while the same blood glucose reading may bediscretized as a normal value in a second timestamp bin.

From the for loop start block 226, the method 200 proceeds to block 228,where the data discretization engine 120 determines appropriate valuediscretization thresholds for the collected signal data for the giventimestamp bin. As discussed above, any suitable technique may be usedfor determining appropriate value discretization thresholds, such asexpert determination, automated determination using the EM algorithm (orother algorithms, or any other suitable technique. At block 230, thedata discretization engine assigns the collected signal data into apredetermined number of signal data bins according to the valuediscretization thresholds. Similar to the discussion above, thediscretized signal data could be organized by copying to a new location,discrete values could be added to records in the patient data store 114,or could be organized using any other suitable technique.

The method 200 then proceeds to the for loop end block 232. If anyfurther timestamp bins remain to be processed, the method 200 returns tothe for loop start block 226 and processes the next timestamp bin.Otherwise, the method 200 proceeds to the for loop end block 234. If anyfurther signals having continuous data values remain to be processed,the method 200 returns to the for loop start block 220 and processes thenext signal. Otherwise, the method 200 has completed processing thecollected signal data, and proceeds to terminal D.

The test results below show the benefits that can be gained fromperforming the method 200 as illustrated and described above. However,in other embodiments, discretization of timestamp and measurement valuesmay be performed separately, such that measurement values are not firstseparated into timestamp bins before being discretized. In someembodiments, some signals may be processed differently from othersignals, such as having thresholds determined by experts versus beingdetermined automatically, being discretized according to timestamp binor overall, and/or with any other difference.

Once the method 200 has completed the set of method steps 204, thecollected signal data has been processed to generate training data. Insome embodiments, the training data may include the collected signaldata stored in the patient data store 114, after it has been altered tobe cleaned and to include discretization values. In some embodiments,the training data may include a cleaned and discretized copy of thecollected signal data separate from the original collected signal data,either stored in the patient data store 114 or stored in some otherlocation accessible to the task optimization system 106.

From terminal D (FIG. 2A), the method 200 proceeds to a set of methodsteps 206 defined between a start terminal (“terminal E”) and an exitterminal (“terminal F”), wherein the training data is processed todetect association rules. From terminal E (FIG. 2D), the method 200proceeds to block 236, where an association rule detection engine 122 ofthe task optimization system 106 processes the set of training data tocalculate a set of first order logic rules. In some embodiments, theApriori algorithm is used to derive the set of first order logic rules.The discretized data are used in the algorithm as inputs and rules arederived by looking back a variable number of days (the “time window”discussed further below). The time window is increased by one day foreach iteration of the Apriori algorithm. In some embodiments, thealgorithm calculates the support and confidence of each implication sothat the method 200 may choose implications meeting qualifying thresholdlimits (as discussed further below). In each subsequent pass, the largeitem sets found in the previous step may be used to generate thecandidate sets (i.e., the largest item sets). The results of each stepare large item sets of qualifying minimum support and confidence in thegiven time window.

Though time units of “days” are primarily discussed herein, this exampleis used for ease of discussion only. In some embodiments, the timewindow for which associations are sought may be measured in other unitsof time, such as weeks, months, hours, portion of day (e.g., morning,afternoon, evening, night), or any other suitable unit of time.

The Apriori algorithm operates substantially as follows: Let I={i₁, i₂,. . . i_(m)} be a superset of all possible task outputs. Let D be a setof events such that D is a subset of I. An association rule is animplication of A implies B where A is a subset of I, B is a subset of I,and the intersection of A and B is empty. The algorithm also calculatesa confidence value, a support value, and a conditional probability valuefor each association rule. Confidence c means that c % of events in Dcontain A and B. Support s indicates s % of events in D contain A or B.Conditional probability p indicates p % of events in D contain B when Ahappens. In some embodiments, these values may be stored along with theassociation rule to enable further filtering and processing of theassociation rules.

Next, at block 238, the association rule detection engine 122 calculatesa contrapositive of each first order logic rule and adds eachcontrapositive logic rule to the set of logic rules. The contrapositivemay also be generated during the execution of the Apriori algorithmalong with the generation of the first order logic rules. Theconfidence, support, and conditional probability for the contrapositivelogic rule are calculated from the set of training data similarly to thecalculation of the same values for the first order logic rule asdiscussed above.

The method 200 then proceeds to a for loop defined between a for loopstart block 240 and a for loop end block 252, wherein the set of logicrules is filtered down to a candidate rule set of association rulesusable to optimize the tasks without losing significant information. Insome embodiments, elements of the filter described in the for loop maybe performed concurrently with the generation of first order logic rulesdiscussed above with respect to block 236 or block 238, but isillustrated and discussed separately herein for ease of discussion. Oneof ordinary skill in the art will recognize that the filtering steps maybe performed at any appropriate place in the overall method 200.

From the for loop start block 240, the method 200 proceeds to block 242,where the association rule detection engine 122 determines a confidencevalue, a support value, and a conditional probability value for thefirst order logic rule. In some embodiments, such values are determinedby the rule generation algorithm, and the previously determined valuesare retrieved at this point. In some embodiments, such values may bedetermined by comparing the current rule to the other generated rules.

Next, the method 200 proceeds to a decision block 244, where adetermination is made regarding whether thresholds and timestamps of thefirst order logic rule are OK. Regarding the thresholds, a predeterminedconfidence value threshold, a predetermined support value threshold, anda predetermined conditional probability value threshold may beestablished based on system settings. The confidence value, the supportvalue, and the conditional probability value for the first order logicrule are compared to the corresponding thresholds to ensure that thecandidate rules meet a minimum level of significance. Regarding thetimestamps, a timestamp of the consequent of the first order logic ruleis compared to a timestamp of the antecedent of the first order logicrule to ensure that the consequent occurs after the antecedent. If anyof the thresholds are not met or if the consequent does not have atimestamp after a timestamp of the antecedent, the result of thedetermination at decision block 244 is NO, and the method 200 proceedsto the for loop start block 240 to process the next logic rule (if any)without adding the current first order logic rule to the candidate ruleset.

Otherwise, if the thresholds are met and the consequent has a timestampafter a timestamp of the antecedent, the result of the determination atdecision block 244 is YES, and the method 200 proceeds to a decisionblock 246. At decision block 246, a determination is made regardingwhether the current first order logic rule is a subset of an existingrule already present in the candidate rule set. If the result of thedetermination at decision block 246 is NO, then the method 200 proceedsto block 248, where the logic rule is added to the candidate rule set.The method 200 then returns to the for loop start block 240 to processthe next logic rule if any remain in the set of logic rules.

Otherwise, if the result of the determination at decision block 246 isYES, then the method 200 proceeds to block 250, where, if theconditional probability of the logic rule is higher than the conditionalprobability of the existing candidate rule, the conditional probabilityof the existing candidate rule is updated to match the conditionalprobability of the current logic rule. The method 200 then returns tothe for loop start block 240 to process the next logic rule if anyremain in the set of logic rules.

Once the for loop has processed all of the logic rules in the set oflogic rules, the method 200 proceeds from the for loop end block 252 toblock 254, where the association rule detection engine 122 stores thecandidate rule set in an association rule data store 116. The method 200then proceeds to terminal F.

From terminal F (FIG. 2A), the method 200 proceeds to a set of methodsteps between a start terminal (“terminal G”) and an exit terminal(“terminal H”), wherein the association rules are used to optimize thedata collection tasks. From terminal G (FIG. 2E), the method 200proceeds to block 256, where the data collection engine 112 reorders oneor more tasks in the task data store based on the stored associationrules. As a nonlimiting example, if an association rule indicates that agiven result to a first data collection task implies a result for asecond data collection task, the first data collection task may beplaced in order before the second data collection task. Next, at block260, the patient monitoring system 102 receives a set of optimized datacollection tasks, the set of optimized data collection tasks includingone or more optimization rules. The method 200 then proceeds to block262, where the patient monitoring system 102 collects data indicated bythe set of optimized data collection tasks, including skipping at leastone task based on an optimization rule. For example, if a first datacollection task is performed and a given value is obtained that matchesan antecedent of an association rule, one or more tasks indicated in theconsequent of the association rule are subsequently skipped because theassociation rule can be used to infer the results of the skipped tasks.In some embodiments, the task skipping may be directed by logic added tothe set of optimized data collection tasks, while in some embodimentsthe patient monitoring system 102 may use the optimization rules todynamically detect when data collection tasks should be skipped. In someembodiments, the actions described with respect to block 262 may beperformed using the same association rules and optimized tasks for morethan one patient, and/or may be performed using the same associationrules and optimized tasks multiple times for the same patient while thepatient is being monitored. In some embodiments, the method 200 may berepeated in its entirety each time additional data is collected for agiven patient, such that the latest data may be included with theprevious training data for optimization and the overall training dataset is kept up-to-date.

The method 200 then proceeds to terminal H, and then from terminal H(FIG. 2A) to an end block where the method 200 terminates.

Test Results

Embodiments of the above system and method have been verified in atleast two studies performed to optimize remote health monitoring tasksfor patients living with diabetes.

In a first study, participants eligible for recruitment were adults withType 2 Diabetes having an HbA1c (a test that indicates how well thepatient is controlling their diabetes) greater than or equal to 7.5, andwho were recently hospitalized. Patients with active malignancy or thoseunable to provide informed consent were excluded, and patients wererandomized to either intervention or control.

In the first study, data was used from 14 study participants assigned tothe intervention arm, with an average participation duration of 59.67days. Patients in the intervention arm were instructed to measure theirblood sugar up to three times a day (morning, afternoon, and evening)and answer four survey questions per day. The defined acceptable rangesfor blood glucose were between 80 and 200 mg/dL. The timestamp valueswere simply discretized as morning, afternoon, and evening based on anexpert determination of appropriate value discretization thresholds forthe timestamps. During the cleaning steps, missing data, multiplemeasurements, and out-of-normal-range values were noted. Existence ofcall logs between a patient and caregivers were also labeled. The dataincluded 1688 instances, and each datum included 26 attributes. Afterdata cleaning, 546 data points remained for analysis by the disclosedmethod.

The disclosed method was utilized with look back windows of one, two,and three days. With a one day look back window, 12 association ruleswere generated, with a minimum confidence of 0.97. With a two day lookback window, two new rules were added, with a minimum confidence of0.978. With a three day look back window, no new rules were added andthe minimum confidence remained 0.978. Accordingly, it was determinedthat the two day look back window was optimal for the processed data.

Using the optimized rule set, the total number of patient tasks wasreduced by an average of 28.6% with negligible information loss.Compared with Flach's algorithm (see Flach, P A. “Confirmation-guideddiscovery of first-order rules with Tertius.” Machine learning, 42(½),61-95. 2001), the embodiment of the present disclosure showed a higherconfidence level (Flach's algorithm provided a maximum confidence levelof 0.52 with a 1-3 day look back window) and higher efficiency.

A second study was performed using a larger data set, and to compareusing expert determination of value discretization thresholds with theautomatically determined value discretization thresholds describedabove. In the second study, participants eligible for recruitment wereadults with Type 2 Diabetes having an HbA1c (a test that indicates howwell the patient is controlling their diabetes) greater than or equal to7.5, and who were recently hospitalized. Patients with active malignancyor those unable to provide informed consent were excluded, and patientswere randomized to either intervention or control. Twenty-one studyparticipants were assigned to the intervention arm, including 18 maleparticipants and three female participants, with an average age of48.13. Average participation duration was 52.23 days. Patients in theintervention arm were instructed to measure their blood sugar up tothree times a day (morning, afternoon, and evening), and to answer fourquestions per day. FIG. 3 illustrates a table 300 that includes theacceptable range for blood glucose values and the four questions thatwere presented along with their discrete answer value choices.

During processing, the timestamps were discretized into threecategories, and blood glucose values in each time category were alsodiscretized into three levels. During cleaning, the collected data wasindexed for missing data and multiple measurements, and the existence ofcall logs between a patient and caregivers were also labeled. Theconfidence value threshold and support threshold were set to 0.95, andthe conditional probability threshold was set to 0.85. The total numberof instances were 1117, and each datum included 54 attributes per day(including the patients' profile).

To find the best discretization method, different discretizationapproaches were applied using: 1) the experts' knowledge utilized inHanefeld and Malherbe's studies (Hanefeld, M. Risk factors formyocardial infarction and death in newly detected NIDDM: the DiabetesIntervention Study, 11-year follow-up, Diabetologia, 39(12), 1577-1583,1996; Malherbe, C. Circadian variations of blood sugar and plasmainsulin levels in man, Diabetologia, 5(6), 397-404, 1969), on bloodglucose and timestamp accordingly; 2) the EM algorithm; and 3) thecombination of experts' knowledge and the EM algorithm.

For experts' knowledge-based discretzation (EKTBD), timestamps werecategorized into three different time periods (Ti), and blood glucosereadings were also categorized into three different levels. Eachtimestamp period is T1: 7:30:00-12:00:00, T2: 12:00:00-16:30:00 and T3:16:30:00-21:00:00; and each blood glucose level is B1: <80 mg/dl, B2:80-200 mg/dl and B3:>200 mg/dl.

For discretizing timestamps only (EMTD), the EM algorithm was applied oncollected timestamps of blood glucose measurements, and experts'knowledge was applied on blood glucose readings. Timestamps werediscretized as T1: 0:00:00-8:29:59, T2: 8:29:59-15:09:45 and T3:15:09:45-23:59:59; and blood glucose readings were discretized as B1:<80 mg/dl, B2: 80-200 mg/dl and B3: >200 mg/dl.

For discretizing blood glucose only (EMBD), the EM algorithm wasutilized on collected blood glucose readings, and experts' knowledge wasapplied on timestamps. Each timestamp period is T1: 7:30:00-12:00:00,T2: 12:00:00-16:30:00 and T3: 16:30:00-21:00:00; and blood glucosereadings were categorized as B1: <170.8 mg/dl, B2: 170.8-274.0 mg/dl andB3: >274.0 mg/dl.

For quantizing both timestamps and blood glucose readings (EMTBD), theEM algorithm was utilized on collected timestamps of blood glucosemeasurements to discretize data into three timestamp bins, and readingscollected in each time period were further discretized into threelevels. In other words, using the method 200 described above, each timeinterval was assigned different discretization thresholds, and thereforeused different standards of categorizing blood glucose data in threedifferent levels. Each discretized timestamp period, as well as mean andstandard deviation values of its three different blood glucose levelsare listed in the table 400 illustrated in FIG. 4. An assumption wasmade that the readings were a mixture of Gaussian distributions, and theintersections of Gaussian curves were found. The obtained B1, B2, B3ranges of T1 (B11, B12, B13) were <166, 166-372, and >372. B21, B22,B23, B31, B32, B33 were <169, 169-265, >265; and <185, 185-318, >318mg/dL accordingly.

The experimental results show that the maximum sliding window size tomake the conditional probabilities of ten best Apriori first order logicrules 1.00 is 4 days in EMTBD, while other methods require 5 days.Therefore, the method 200 described above has been shown reduce therequired time windows to 4 days to reach the maximum conditionalprobability, while utilizing experts' knowledge requires 5 days worth ofdata to reach the same conditional probability. Furthermore,discretizing timestamp and quantizing blood glucose data of each timeframe using the EM algorithm yields less computational power andmaximizes information gain in a shorter period of time compared to usingexperts' knowledge-based methods.

Moving on to association rule mining, FIG. 5 illustrates a chart 500that shows a count of first order logic rules added for various timewindow values. The proposed algorithm had optimal results with a lookback window of 5 days. The minimum confidence peaks at 1.00 at 2 to 5days. Compared to the first study which utilizes experts' knowledge fordiscretization, the combination of EM algorithm-based discretization andthe Apriori algorithm for detecting association rules shows improvementof 1.292% of minimum confidence.

The chart 500 shows the number of new rules added or updated withincreasing window size. A total of 7 rules were added with a window sizeof one day and a total of 19 rules were updated with a window size of 5days. No rules were added or updated with a look-back window of morethan 5 days. Compared with the first study, a larger amount of data (546data in the first study versus 1117 data in this study after datacleaning) and the EM algorithm-based discretization yields more ruleswith larger size of sliding window from the Apriori algorithm. The totalnumber of patient tasks was reduced by up to 76.19% with negligibleinformation loss. For example, as shown in the table 600 in FIG. 6, itwas found that responses to Q3 and Q4 can be inferred from each other.

Although the two studies described above relate to remote monitoring ofpatients with diabetes, one of ordinary skill in the art will recognizethat the techniques described above can easily be adapted to optimizemonitoring tasks for any other health condition that is monitoredremotely. As nonlimiting examples, patients with chronic heart failure,patients with sleep apnea, patients with COPD, and patients withhypertension may all be monitored in similar ways to those describedabove. That is, for each of these conditions, the patient may beinstructed to periodically answer one or more survey questions, and/ormay be instructed to periodically provide a physical measurement (suchas a blood pressure reading, a blood glucose level, motion/activitydetection, and/or the like). For any of these conditions or any othercondition that uses similar remote monitoring, the techniques describedabove can be used to optimize the data collection tasks without undueexperimentation.

Exemplary Computing Device

FIG. 7 is a block diagram that illustrates aspects of an exemplarycomputing device 700 appropriate for use with embodiments of the presentdisclosure. While FIG. 7 is described with reference to a computingdevice that is implemented as a device on a network, the descriptionbelow is applicable to servers, personal computers, mobile phones, smartphones, tablet computers, embedded computing devices, and other devicesthat may be used to implement portions of embodiments of the presentdisclosure. Moreover, those of ordinary skill in the art and others willrecognize that the computing device 700 may be any one of any number ofcurrently available or yet to be developed devices.

In its most basic configuration, the computing device 700 includes atleast one processor 702 and a system memory 704 connected by acommunication bus 706. Depending on the exact configuration and type ofdevice, the system memory 704 may be volatile or nonvolatile memory,such as read only memory (“ROM”), random access memory (“RAM”), EEPROM,flash memory, or similar memory technology. Those of ordinary skill inthe art and others will recognize that system memory 704 typicallystores data and/or program modules that are immediately accessible toand/or currently being operated on by the processor 702. In this regard,the processor 702 may serve as a computational center of the computingdevice 700 by supporting the execution of instructions.

As further illustrated in FIG. 7, the computing device 700 may include anetwork interface 710 comprising one or more components forcommunicating with other devices over a network. Embodiments of thepresent disclosure may access basic services that utilize the networkinterface 710 to perform communications using common network protocols.The network interface 710 may also include a wireless network interfaceconfigured to communicate via one or more wireless communicationprotocols, such as WiFi, 2G, 3G, LTE, WiMAX, Bluetooth, and/or the like.

In the exemplary embodiment depicted in FIG. 7, the computing device 700also includes a storage medium 708. However, services may be accessedusing a computing device that does not include means for persisting datato a local storage medium. Therefore, the storage medium 708 depicted inFIG. 7 is represented with a dashed line to indicate that the storagemedium 708 is optional. In any event, the storage medium 708 may bevolatile or nonvolatile, removable or nonremovable, implemented usingany technology capable of storing information such as, but not limitedto, a hard drive, solid state drive, CD ROM, DVD, or other disk storage,magnetic cassettes, magnetic tape, magnetic disk storage, and/or thelike.

As used herein, the term “computer-readable medium” includes volatileand non-volatile and removable and non-removable media implemented inany method or technology capable of storing information, such ascomputer readable instructions, data structures, program modules, orother data. In this regard, the system memory 704 and storage medium 708depicted in FIG. 7 are merely examples of computer-readable media.

Suitable implementations of computing devices that include a processor702, system memory 704, communication bus 706, storage medium 708, andnetwork interface 710 are known and commercially available. For ease ofillustration and because it is not important for an understanding of theclaimed subject matter, FIG. 7 does not show some of the typicalcomponents of many computing devices. In this regard, the computingdevice 700 may include input devices, such as a keyboard, keypad, mouse,microphone, touch input device, touch screen, tablet, and/or the like.Such input devices may be coupled to the computing device 700 by wiredor wireless connections including RF, infrared, serial, parallel,Bluetooth, USB, or other suitable connections protocols using wirelessor physical connections. Similarly, the computing device 700 may alsoinclude output devices such as a display, speakers, printer, etc. Sincethese devices are well known in the art, they are not illustrated ordescribed further herein.

As will be appreciated by one skilled in the art, the specific routinesdescribed above in the flowcharts may represent one or more of anynumber of processing strategies such as event-driven, interrupt-driven,multi-tasking, multi-threading, and the like. As such, various acts orfunctions illustrated may be performed in the sequence illustrated, inparallel, or in some cases omitted. Likewise, the order of processing isnot necessarily required to achieve the features and advantages, but isprovided for ease of illustration and description. Although notexplicitly illustrated, one or more of the illustrated acts or functionsmay be repeatedly performed depending on the particular strategy beingused. Further, these FIGURES may graphically represent code to beprogrammed into a computer readable storage medium associated with acomputing device.

While illustrative embodiments have been illustrated and described, itwill be appreciated that various changes can be made therein withoutdeparting from the spirit and scope of the claimed subject matter.

The invention claimed is:
 1. A computer-implemented method of optimizingdata collection tasks for patient monitoring, the method comprising:performing, by a first computing device, a set of data collection tasksto obtain a set of monitoring data, the set of monitoring datacomprising sensor data measured from a patient; processing, by the firstcomputing device or a second computing device, the set of monitoringdata to detect one or more association rules between two or more datacollection tasks in the set of data collection tasks, wherein processingthe set of monitoring data includes: determining a candidate set offirst order logic rules based on the set of monitoring data, and foreach first order logic rule in the candidate set of first order logicrules: in response to determining that a timestamp of a consequent ofthe first order logic rule is larger than a timestamp of an antecedentof the first order logic rule, and that an implication of the firstorder logic rule is not a subset of any rules in the detected one ormore association rules, adding the first order logic rule to thedetected one or more association rules; optimizing, by the firstcomputing device or the second computing device, the set of datacollection tasks based on the detected association rules, whereinoptimizing the set of data collection tasks includes: in response to adata collection task in the set of data collection tasks is performed toobtain a value that matches an antecedent of an association rule in thedetected one or more association rules, skipping one or more datacollection tasks indicated as a consequent of the association rule; andcontinuing obtaining an additional set of monitoring data by performingthe optimized set of data collection tasks by the first computingdevice.
 2. The computer-implemented method of claim 1, whereinprocessing the set of monitoring data to detect one or more associationrules between two or more data collection tasks in the set of datacollection tasks includes discretizing at least one signal havingcontinuous data values included in the set of monitoring data.
 3. Thecomputer-implemented method of claim 2, wherein discretizing at leastone signal having continuous data values included in the set ofmonitoring data comprises: determining discretization thresholds fortimestamps assigned to the at least one signal to cluster the associateddata into a predetermined number of timestamp bins; and determiningdiscretization thresholds for continuous data values of the at least onesignal for each timestamp bin to cluster the associated continuous datavalues into a predetermined number of signal data bins for eachtimestamp bin.
 4. The computer-implemented method of claim 3, whereindetermining discretization thresholds includes utilizing expectationmaximization.
 5. The computer-implemented method of claim 1, whereinprocessing the set of monitoring data to detect one or more associationrules between two or more data collection tasks in the set of datacollection tasks includes: calculating a set of first order logic rulesimplied by the set of monitoring data; and wherein determining acandidate set of first order logic rules based on the set of monitoringdata includes: determining the candidate set of first order logic rulesof the set of first order logic rules that have a confidence valuegreater than a confidence value threshold, a support value greater thana support value threshold, and a conditional probability value greaterthan a conditional probability value threshold.
 6. Thecomputer-implemented method of claim 5, wherein processing the set ofmonitoring data to detect one or more association rules between two ormore data collection tasks in the set of data collection tasks furtherincludes: calculating at least one contrapositive logic rule based on atleast one first order logic rule in the candidate set of first orderlogic rules; and adding the contrapositive logic rule to the candidateset of first order logic rules.
 7. The computer-implemented method ofclaim 5, wherein processing the set of monitoring data to detect one ormore association rules between two or more data collection tasks in theset of data collection tasks further includes: for each first orderlogic rule in the candidate set of first order logic rules: in responseto determining that a timestamp of a consequent of the first order logicrule is larger than a timestamp of an antecedent of the first orderlogic rule, that an implication of the first order logic rule is asubset of a detected rule in the detected one or more association rules,and that the first order logic rule has a higher conditional probabilitythan the detected rule, updating the detected rule with the higherconditional probability of the first order logic rule.
 8. Thecomputer-implemented method of claim 5, wherein optimizing the set ofdata collection tasks includes reordering the data collection tasks inthe set of data collection tasks based on the detected association rulesto increase a likelihood that a result of a subsequent task is impliedby a result of a precedent task.
 9. The computer-implemented method ofclaim 1, wherein performing a set of data collection tasks includesobtaining a value representing a physical measurement obtained by aphysical data sensor device.
 10. The computer-implemented method ofclaim 1, wherein performing a set of data collection tasks includes:presenting a question to a patient using an interactive sensor device;and receiving a response to the question using the interactive sensordevice.
 11. The computer-implemented method of claim 1, furthercomprising inferring, by the first computing device or the secondcomputing device, results of the skipped one or more data collectiontasks from the association rule in the detected one or more associationrules.
 12. A system for patient monitoring, comprising: a patient dataprocessing system including at least one computing device, wherein theat least one computing device comprises at least one processor and amemory, and wherein the at least one computing device is configured to:retrieve a set of data collection tasks from a task data store; performthe set of data collection tasks to obtain a set of monitoring data, theset of monitoring data comprising sensor data measured from a patient;and store the set of monitoring data in a patient data store; and a taskoptimization system including at least one computing device, wherein theat least one computing device comprises at least one processor and amemory, and wherein the at least one computing device is configured to:retrieve the set of monitoring data from the patient data store; processthe set of monitoring data to detect one or more association rulesbetween two or more data collection tasks in the set of data collectiontasks, wherein the at least one computing device is further configuredto: determine a candidate set of first order logic rules based on theset of monitoring data, and for each first order logic rule in thecandidate set of first order logic rules: in response to determiningthat a timestamp of a consequent of the first order logic rule is largerthan a timestamp of an antecedent of the first order logic rule, andthat an implication of the first order logic rule is not a subset of anyrules in the detected one or more association rules, add the first orderlogic rule to the detected one or more association rules; optimize theset of data collection tasks based on the detected association rules;and store the optimized set of data collection tasks in the task datastore; wherein the at least one computing device included in the patientdata processing system is further configured to obtain an additional setof monitoring data by performing the optimized set of data collectiontasks.
 13. The system of claim 12, wherein processing the set ofmonitoring data to detect one or more association rules between two ormore data collection tasks in the set of data collection tasks includesdiscretizing at least one signal having continuous data values includedin the set of monitoring data.
 14. The system of claim 13, whereindiscretizing at least one signal having continuous data values includedin the set of monitoring data comprises: determining discretizationthresholds for timestamps assigned to the at least one signal to clusterthe associated data into a predetermined number of timestamp bins; anddetermining discretization thresholds for continuous data values of theat least one signal for each timestamp bin to cluster the associatedcontinuous data values into a predetermined number of signal data binsfor each timestamp bin.
 15. The system of claim 14, wherein determiningdiscretization thresholds includes utilizing expectation maximization.16. The system of claim 12, wherein processing the set of monitoringdata to detect one or more association rules between two or more datacollection tasks in the set of data collection tasks includes:calculating a set of first order logic rules implied by the set ofmonitoring data; determining a candidate set of first order logic rulesof the set of first order logic rules that have a confidence valuegreater than a confidence value threshold, a support value greater thana support value threshold, and a conditional probability value greaterthan a conditional probability value threshold; and for each first orderlogic rule in the candidate set of first order logic rules: in responseto determining that a timestamp of a consequent of the first order logicrule is larger than a timestamp of an antecedent of the first orderlogic rule, and that an implication of the first order logic rule is nota subset of any rules in the detected one or more association rules,adding the first order logic rule to the detected one or moreassociation rules.
 17. The system of claim 16, wherein processing theset of monitoring data to detect one or more association rules betweentwo or more data collection tasks in the set of data collection tasksfurther includes: calculating at least one contrapositive logic rulebased on at least one first order logic rule in the candidate set offirst order logic rules; and adding the contrapositive logic rule to thecandidate set of first order logic rules.
 18. The system of claim 16,wherein processing the set of monitoring data to detect one or moreassociation rules between two or more data collection tasks in the setof data collection tasks further includes: for each first order logicrule in the candidate set of first order logic rules: in response todetermining that a timestamp of a consequent of the first order logicrule is larger than a timestamp of an antecedent of the first orderlogic rule, that an implication of the first order logic rule is asubset of a detected rule in the detected one or more association rules,and that the first order logic rule has a higher conditional probabilitythan the detected rule, updating the detected rule with the higherconditional probability of the first order logic rule.
 19. The system ofclaim 16, wherein optimizing the set of data collection tasks includesreordering the data collection tasks in the set of data collection tasksbased on the detected association rules to increase a likelihood that aresult of a subsequent task is implied by a result of a precedent task.20. The system of claim 12, further comprising at least one physicaldata sensor device, and wherein performing a set of data collectiontasks includes obtaining a value representing a physical measurementobtained by the at least one physical data sensor device.
 21. The systemof claim 12, further comprising at least one interactive sensor device,and wherein performing a set of data collection tasks includes:presenting a question to a patient using the interactive sensor device;and receiving a response to the question using the interactive sensordevice.
 22. The system of claim 12, wherein optimizing the set of datacollection tasks includes: in response to a data collection task in theset of data collection tasks is performed to obtain a value that matchesan antecedent of an association rule in the detected one or moreassociation rules, skipping one or more data collection tasks indicatedas a consequent of the association rule.
 23. A non-transitorycomputer-readable medium having computer-executable instructions storedthereon that, in response to execution by one or more processors of acomputing device, cause the computing device to perform the method asrecited in claim 1.